If you have ever owned a shotgun or rifle, you probably have sought to protect your gun from the weather, and from accidental damage. Gun covers and gun cases have been widely available for such purposes for hundreds of years. There are many different types of gun cases and covers, most of which are waterproof. They protect the entire gun, and they are generally very effective when used for gun storage.
However, during a hunting trip, an ordinary gun cover cannot be repeatedly removed and replaced with great convenience. And while the cover is off the gun, you cannot readily place it in your pocket. It can be a real nuisance to carry, when not in use. Also, if you were to fall or drop the gun while the cover is off, there is a good chance dirt, mud, snow or other debris may enter the muzzle or the chamber. Any obstruction in the barrel becomes an immediate danger to the user and all nearby hunters, since the gun may explode if fired.